Pharmacokinetics and Relative Bioavailability of Flunarizine Capsules in 10 Healthy Volunteers

Objective: To compare the pharmacokinetics and relative bioavailability of flunarizine capsule A(Bohai Pharmaceutical,Tangshan,lot No:970901) and capsule B(Xichuan Pharmaceutical, Henan, lot No: 970129). Methods: A single oral dose of 12mg flunarizine of each kind of capsules was given to 10 Chinese healthy male volunteers respectively in an open,randomized crossover study. Plasma levels were determined with HPLC UV method. Results: The plasma concentration time curve was fitted to 1 compartment open model with a first order and lag time absorption. The major pharmacokinetic parameters of capsule A and B were shown respectively as following:C max (43 7±6 2) mg·L -1 and (47 4±13 8) mg·L -1 ; T max (3 04±0 53)h and (3 28±1 04)h; T 1/2ka (1 14±0 68)h and (1 28±0 92)h; T 1/2ke ( 5 44±2 41)h and (5 53±2 71)h; AUC (507 0±151 0) mg·h·L 1 and (534 1±116 0) mg·h·L 1 ; MRT (8 20±1 53)h and (8 34±1 41)h. There were no significant differences between the pharmacokinetic parameters of capsule A and B. The relative bioavailability of the capsule A was 97 5%±30 9% of that of the capsule B. Conclusion: The two kinds of Flunarizine capsules had the equivalent biological effects.